Feed mechanism for syringe pump

Abstract

A medical device, such as a syringe driver assembly having driver means for imparting translational movement to a member, the driver means comprising a motor driven unthreaded shaft ( 200 ), at least one bearing ( 260, 270, 280 ) mounted obliquely to the shaft and having at least one point of contact therewith, and an actuator ( 800 ) linked to the at least one bearing for contacting the member wherein rotation of the shaft causes movement of the bearing along the shaft to affect movement of the actuator.

1 - 21 . (canceled)  
   
   
       22 . A syringe driver assembly for imparting translational movement to a syringe plunger, comprising: 
 a. a motor driven unthreaded shaft,    b. at least one bearing mounted obliquely to the shaft and having at least one point of contact therewith, and    c. an actuator linked to at least one of the bearings for contacting a thumbplate of the plunger, wherein rotation of the shaft causes movement of the actuator-linked bearing along the shaft to affect movement of the actuator.    
   
   
       23 . The syringe driver assembly of  claim 22  wherein therein is but a single bearing and the shaft is supported by a rotary member at least one point along the length.  
   
   
       24 . The syringe driver assembly of  claim 23  wherein the rotary member is on an opposite side of the shaft relative to the contact point of the bearing.  
   
   
       25 . The syringe driver assembly of  claim 22  wherein at least three bearings are provided with alternate bearings being mounted at the same angle relative to the shaft and adjacent bearings being mounted at an opposing angle relative to the shaft.  
   
   
       26 . The syringe driver assembly of  claim 25  wherein each bearing has a bore through which the shaft passes, with the bore being larger than the shaft outer circumference.  
   
   
       27 . The syringe driver assembly of  claim 26  wherein the bearing has a pointed inner profile.  
   
   
       28 . The syringe driver assembly as claimed in  claim 26  wherein the bearing has a flat inner profile with a chamfered inner race.  
   
   
       29 . The syringe driver assembly of  claim 28  wherein each bearing is angled with respect to the shaft such that it contacts the shaft at least two points.  
   
   
       30 . The syringe driver assembly of  claim 29  wherein three bearings are provided, with one of the outer bearings and the other of the outer bearing and the central bearing contacting the bottom of the shaft and the central bearing contacting the top of the shaft.  
   
   
       31 . The syringe driver assembly  claim 30  wherein the angle of inclination of each bearing relative to the shaft is less than 45 degrees.  
   
   
       32 . The syringe driver assembly of  claim 25  wherein the inclined bearings are symmetrically spaced in one plane perpendicular to the shaft axis and the outer races of the bearings make radial contact with the shaft.  
   
   
       33 . The syringe driver assembly of  claim 32  wherein the bearing is spring loaded.  
   
   
       34 . The syringe driver assembly of  claim 33  wherein the bearing is housed within a carriage that is moveable with respect to the shaft.  
   
   
       35 . The syringe driver assembly of  claim 33  wherein the carriage is connected to the actuator.  
   
   
       36 . The syringe driver assembly of  claim 35  wherein the carriage is provided with guides.  
   
   
       37 . The syringe driver assembly of  claim 36  further comprising means for manually disengaging at least one bearing to enable sliding movement independently of the shaft.  
   
   
       38 . The syringe driver assembly of  claim 37  wherein at least one bearing is spring-loaded with respect to the shaft and operation of the spring mechanism disengages that bearing from the shaft.  
   
   
       39 . The syringe driver assembly of  claim 37  wherein manual disengagement is affected by movement of a housing containing a bearing in a direction transverse to the shaft to lift the bearing from the shaft.  
   
   
       40 . The syringe driver assembly of  claim 39  further comprising a cam and lever for lifting the bearing from the shaft.  
   
   
       41 . The syringe driver assembly of  claim 22  further comprising automatic means for reversing direction of travel of the bearings and actuator along the shaft.  
   
   
       42 . The syringe driver assembly of  claim 41  wherein the bearing including adjustable biasing means.